I think you nailed it with a simple demonstration that the oil gallery misalignment may not be the issue. The tiny jets may have been clogged on early models and starving the cam of oil. Your test shows that a clean jet supply's enough oil. Many other videos say the filter is a bad idea. The filter volume can stand much more contaminants than a tiny jet orifice. I guess the guys at KTM are not so stupid. It maybe that the screen may need replacement from time to time. This is better than clogged squirter jets. Great job! Your video is the most plausible video I have seen on this subject. Most times the simplest answer is the right one.
I agree that jet clogging is the problem. The cross-drilling argument is lacking, IMO. If the downhole were out of position, both opposing jets would be starved for oil, so cam lobe failure would always occur in opposing pairs. The evidence does not support that theory. I would like to know if KTM monitors high oil pressure on the head. If so, it would indicate that the thimble filter needs to be changed.
nobody said that the orifice size is the issue ... you need small hole to increase pressure for th oil to squirt,the problem is in offset between vertical passage and the threaded with the jet...
you are absolutely correct it needs that size orifice to cause the pressure to squirt and create enough back pressure for good healthy head pressure to keep the rest of the camshaft journals lubricated, but they can easily clog up with debris if the oil going to them is not filtered good especially any small shavings, and some of the mechanics that had taken out the oil jets to look inside said they found particles in the jets that restricted the oil to the damaged cam lobes.
IMHO: Might be a hell of a lot cheaper to replace the oil pressure spring in the oil pump. KTM lightened up the spring on these models (yup... reduced pressure). CF (Chinese version) left the spring in the original strength on their models.
The screen is in every model of 790/890 model since 2020. The 2019 790 (like mine) doesn't have the additional screen, and it can not be retrofitted because the head is not machined to accommodate it.
Does sharing oil with the transmission and passing clutch material thru the screen increase the risk of the thimble screen clogging over time? Unlike a car, with a dry clutch, the use of a filter in a motorcycle head couple with shared oil seems concerning to me, but could be paranoia. Perhaps this screen is a maintenance item every XX thousand of miles? Also, my Tenere 700 has hollow cams with passages on the bearing faces. These go forever. I love my Norden, but this still seems like a band-aid repair vs following industry best practices.
The service manual shows to take out the thimble screen and clean it and reinstall it back into the cylinder head just under the camshaft bridge after you make any valve adjustments, or you can buy a new one they aren't expensive.
A 10 ml syringe can produce up to 50 psi of pressure, remember atmospheric pressure is approx 14.7 psi. The issue is documented elsewhere with these heads as the misaligned oil galleries and the Jets are fine.
Whether its filtration, offset cross drilling of oil galleries' or plugged jets, I really don't care anymore. I just want KTM to move forward by engineering all this shite out and making the best product for we the end user. For off-road use, the balanced geometric design of KTM ADV line of bikes is unmatched. Now, give us the reliability of a Japanese motor so we can all get back to the most important argument, which is "There is never enough time to enjoy the bike we love the most." I suspect that if KTM does not correct this problem for existing bikes, they will be finished as an ADV brand at the very least. Sadly, they will have their own self-inflated egos to blame.
What if the metal debris is not from the oil supply. Rather from the cam journals. Since cam journal gallery and these oil jet gallery are shared and have no filter
Not saying it couldn't happen, and a very good point you brought out, although it shouldn't happen as long as there is plenty of oil supplied to the journals in the first place to keep the journals from being galled out that would push aluminum shavings into the oil jets. So the objective would be a clean assembled engine with good filtered oil from the bottom to the top by a good oil pump. Thank you for your input.
The service manual shows to take out the thimble screen and clean it and reinstall it back into the cylinder head just under the camshaft bridge after you make any valve adjustments, or you can buy a new one they are serviceable and they aren't expensive.
Not a bad theory, however remember the highest shear rate is between the cam and the follower and oils with a wide viscosity spread don’t have as good of shear strength as ones with a tighter spread. The pump ability between a 20w50 and a 10w50 at reasonable temperatures above freezing is marginal at best.
so far the people and mechanics that I have talked to that actually had taken out the oil jets where the cam lobes where affected said they had found small shavings and particles stuck in the small end of the oil jet nozzles.
I was wondering, later models have this filter in the head. Is the head itself also a different part or can the filter be placed in an older head ? Also heard they created wider finger followers to reduce pressure on the camshaft. The solution seems like combination of multiple relatively small changes I was also surprised (no evidence for it) everyone claims the problem is mainly found in the adventure type bikes and not in the 890R engines. Was the solution (filter, wider followers) already implemented in those heads or is there another reason there's less problems in that engine. Or maybe the problem is just as common there as in the adventure engines. Lot's of questions... and serious doubt if I should by an 890R, I really really dig that motorcycle, but it has to be reliable.
Just guessing, but I theorize that the issue is showing up sooner on the ADV bikes because they rack up miles quicker than the other models. Because the people that buy ADV bikes are hardcore riders and can rack up thousands of miles 15K to 30K in just a couple of years.
@@spartanx169x Could be but there are multiple examples with very low mileage that already have a lot of wear. And some bike don't seem to have the issue at all... Quite weird.
I did see a 2019 790 cylinder head that seemed to be machined in a manner that the filter could possibly be installed, but I haven't tried it to see if the filter can be placed into it, I'll try and get my hands on one of the early 790 2019 cylinder heads to check for myself and post to this channel for everyone interested, and thank you for your comments.
They designed it this way to reduce the head size I believe. This engine is much more compact compared to a Honda or Suzuki engine of the same size. Also finger followers provide a lot more wear on surfaces compared to a shim under bucket setup.
The issue is oil starvation, nothing to do with camshaft hardness or jet size. The filter screen is a useless modification as it's downstream of the paper element. Something is restricting the oil flow, assuming the oil pump is sized correctly to maintain the required flow and, therefore, pressure.
KTM made a big mistake when they have designed that engine, and they don’t take their responsability towards the poor owners, which is very very bad, but once they have discovered the problem I wouldn’t believe they would not be able to redesign what needs to be redesigned, and if they came to the conclusion it is solved by adding a filter, I would assume they know what they’re doing and wouldn’t take any chance to propagate further this problem. So I would trust that the filter is the solution.
You would have thought after the 690’s roller rockers failures back several years , that KTM would have learnt how delicate top ends are , but looks like their Arrogance problem is still there.
I would also shim the pressure relief valve on the oil pump to ensure adequate pressure to get the upper part of the head supplied. Either way this is amateur night at KTM. What a way to shoot yourself in the foot.
I think you nailed it with a simple demonstration that the oil gallery misalignment may not be the issue. The tiny jets may have been clogged on early models and starving the cam of oil. Your test shows that a clean jet supply's enough oil. Many other videos say the filter is a bad idea. The filter volume can stand much more contaminants than a tiny jet orifice. I guess the guys at KTM are not so stupid. It maybe that the screen may need replacement from time to time. This is better than clogged squirter jets. Great job! Your video is the most plausible video I have seen on this subject. Most times the simplest answer is the right one.
I agree that jet clogging is the problem. The cross-drilling argument is lacking, IMO. If the downhole were out of position, both opposing jets would be starved for oil, so cam lobe failure would always occur in opposing pairs. The evidence does not support that theory.
I would like to know if KTM monitors high oil pressure on the head. If so, it would indicate that the thimble filter needs to be changed.
nobody said that the orifice size is the issue ... you need small hole to increase pressure for th oil to squirt,the problem is in offset between vertical passage and the threaded with the jet...
you are absolutely correct it needs that size orifice to cause the pressure to squirt and create enough back pressure for good healthy head pressure to keep the rest of the camshaft journals lubricated, but they can easily clog up with debris if the oil going to them is not filtered good especially any small shavings, and some of the mechanics that had taken out the oil jets to look inside said they found particles in the jets that restricted the oil to the damaged cam lobes.
IMHO: Might be a hell of a lot cheaper to replace the oil pressure spring in the oil pump.
KTM lightened up the spring on these models (yup... reduced pressure).
CF (Chinese version) left the spring in the original strength on their models.
i just checked KTM parts katalogue, this filter is listed for all years: 2024 890 dv, 2022 890 adv and 790adv 2022.
The screen is in every model of 790/890 model since 2020. The 2019 790 (like mine) doesn't have the additional screen, and it can not be retrofitted because the head is not machined to accommodate it.
Does sharing oil with the transmission and passing clutch material thru the screen increase the risk of the thimble screen clogging over time? Unlike a car, with a dry clutch, the use of a filter in a motorcycle head couple with shared oil seems concerning to me, but could be paranoia. Perhaps this screen is a maintenance item every XX thousand of miles? Also, my Tenere 700 has hollow cams with passages on the bearing faces. These go forever. I love my Norden, but this still seems like a band-aid repair vs following industry best practices.
The service manual shows to take out the thimble screen and clean it and reinstall it back into the cylinder head just under the camshaft bridge after you make any valve adjustments, or you can buy a new one they aren't expensive.
A 10 ml syringe can produce up to 50 psi of pressure, remember atmospheric pressure is approx 14.7 psi.
The issue is documented elsewhere with these heads as the misaligned oil galleries and the Jets are fine.
Some have found a problem with where it is cross drilled and slightly off centre so reducing flow of oil, just a thought
These are all off center and it seems to be purposely done in all the 790/890 cylinder heads.
Whether its filtration, offset cross drilling of oil galleries' or plugged jets, I really don't care anymore. I just want KTM to move forward by engineering all this shite out and making the best product for we the end user. For off-road use, the balanced geometric design of KTM ADV line of bikes is unmatched. Now, give us the reliability of a Japanese motor so we can all get back to the most important argument, which is "There is never enough time to enjoy the bike we love the most." I suspect that if KTM does not correct this problem for existing bikes, they will be finished as an ADV brand at the very least. Sadly, they will have their own self-inflated egos to blame.
Size 50 means 0,5mm. My 790 Duke is a 2020 model and it has the oilscreen. Thank you!
What are the symptoms that the camshafts are damaged, how do you find out about it?
What if the metal debris is not from the oil supply. Rather from the cam journals. Since cam journal gallery and these oil jet gallery are shared and have no filter
Not saying it couldn't happen, and a very good point you brought out, although it shouldn't happen as long as there is plenty of oil supplied to the journals in the first place to keep the journals from being galled out that would push aluminum shavings into the oil jets. So the objective would be a clean assembled engine with good filtered oil from the bottom to the top by a good oil pump. Thank you for your input.
Hmmm...do you know if the thimble filter is a service item? Maybe to be removed and cleaned when checking the valve clearances.
The service manual shows to take out the thimble screen and clean it and reinstall it back into the cylinder head just under the camshaft bridge after you make any valve adjustments, or you can buy a new one they are serviceable and they aren't expensive.
@@cliftonsr Thanks for the info.
I would be so pissed if Honda ever pulled this kinda shit that I would never be able to fully trust them again.
That's because Honda would never do something like this.
Since the oil passagesnare very small, might be best to use an oil with 5w50 viscosity that circulate faster than 10w50 or 15w50.
Not a bad theory, however remember the highest shear rate is between the cam and the follower and oils with a wide viscosity spread don’t have as good of shear strength as ones with a tighter spread. The pump ability between a 20w50 and a 10w50 at reasonable temperatures above freezing is marginal at best.
The issue isnt jets blocking, its the machining of the oil galleries being misaligned reducing the oil flow to the jet.
so far the people and mechanics that I have talked to that actually had taken out the oil jets where the cam lobes where affected said they had found small shavings and particles stuck in the small end of the oil jet nozzles.
@@cliftonsr yeah, more than likely pieces of the cam lobes.
I was wondering, later models have this filter in the head. Is the head itself also a different part or can the filter be placed in an older head ?
Also heard they created wider finger followers to reduce pressure on the camshaft. The solution seems like combination of multiple relatively small changes
I was also surprised (no evidence for it) everyone claims the problem is mainly found in the adventure type bikes and not in the 890R engines. Was the solution (filter, wider followers) already implemented in those heads or is there another reason there's less problems in that engine. Or maybe the problem is just as common there as in the adventure engines.
Lot's of questions... and serious doubt if I should by an 890R, I really really dig that motorcycle, but it has to be reliable.
Just guessing, but I theorize that the issue is showing up sooner on the ADV bikes because they rack up miles quicker than the other models. Because the people that buy ADV bikes are hardcore riders and can rack up thousands of miles 15K to 30K in just a couple of years.
@@spartanx169x Could be but there are multiple examples with very low mileage that already have a lot of wear. And some bike don't seem to have the issue at all... Quite weird.
I did see a 2019 790 cylinder head that seemed to be machined in a manner that the filter could possibly be installed, but I haven't tried it to see if the filter can be placed into it, I'll try and get my hands on one of the early 790 2019 cylinder heads to check for myself and post to this channel for everyone interested, and thank you for your comments.
@@cliftonsr Many thanks to you for creating some clarity in this case.
My friend just bough duke 790 weeks ago rip
They designed it this way to reduce the head size I believe. This engine is much more compact compared to a Honda or Suzuki engine of the same size. Also finger followers provide a lot more wear on surfaces compared to a shim under bucket setup.
The issue is oil starvation, nothing to do with camshaft hardness or jet size. The filter screen is a useless modification as it's downstream of the paper element.
Something is restricting the oil flow, assuming the oil pump is sized correctly to maintain the required flow and, therefore, pressure.
KTM made a big mistake when they have designed that engine, and they don’t take their responsability towards the poor owners, which is very very bad, but once they have discovered the problem I wouldn’t believe they would not be able to redesign what needs to be redesigned, and if they came to the conclusion it is solved by adding a filter, I would assume they know what they’re doing and wouldn’t take any chance to propagate further this problem. So I would trust that the filter is the solution.
You would have thought after the 690’s roller rockers failures back several years , that KTM would have learnt how delicate top ends are , but looks like their Arrogance problem is still there.
Can't be good for KTM resale values.
so sad and true.
I wonder how many million dollars that little screen cost the bottom line...
I would also shim the pressure relief valve on the oil pump to ensure adequate pressure to get the upper part of the head supplied. Either way this is amateur night at KTM. What a way to shoot yourself in the foot.
I did. Twice. Second time with this head.
sorry to hear that I would be bummed out.
What kind of motor brand is it judging by the sound,..Hhrmmm,.. erhmmmm,.. brhmmm!
very small hole and large PSI.